Between the middle of the 19th century and the early 21st, the heaviest wild breeding bird in the UK was the mute swan at around 11kg. In 2004, a retired policeman from Wiltshire hatched a plan, and later an egg, which has raised that weight by nearly half. David Waters and his team have reintroduced the great bustard.

"It has been a long and painful route," says David. "The basic motivation is: I thought it was a good idea and nobody else seemed prepared to undertake it. If there's one thing I hate in life, it's the phrase, 'someone ought to do something'."

In 2007, the project recorded its first great bustard nest. There were a couple more in 2008 and the first chick hatched in 2009. "We've had nests every year since then," says David.

You can see Britain's only bustards for yourself at the Great Bustard project on the edge of Salisbury Plain. Book a visit and you'll be met in a car park and taken to a viewing hide by Land Rover. The birds are wild and free flying. Your first glimpse of these birds, with their 2.5-metre wingspans, is, says David, an experience not to be missed.

The naturalist Simon King is a fan. "How marvellous it is that one of the planet's heaviest flying birds, perhaps the heaviest, once again breeds on British soil," he says. "The Great Bustard project is testament to the care, dedication and vision of the team that have nurtured the release birds to the point where there are now free ranging birds raising families of their own."

Britain's only bustard was hunted to extinction, with the last one probably killed in the 1840s. Now it is fox control by hunters that's helping to keep it alive. The bird's best boon, however, is the natural paradise that is the military training area on Salisbury Plain.

The Ministry of Defence (MoD) owns 94,000 acres of Salisbury Plain. Access to much of the area is restricted and the risk of coming across unexploded ordnance helps keep visitors to the public footpaths (details can be downloaded from bit.ly/greyplain).

David thinks it's the lack of disturbance that does most to make his project successful. "If you go up in a Land Rover, you don't disturb the birds at all," he says. "If you go on foot, you see the birds slip off their nests. People who go searching for them on their own either upset the great bustards, the stone curlews, the military, or me."

•What to see: The Great Bustard project (01980 671466, greatbustard.org). Visits cost £10 per person (90 mins duration) and typically run on Tue-Sun at 9.30am, 11.30am or 2pm